Wrist and hand musculoskeletal disorders (MSDs) are common among workers and are associated with extreme joint postures that include wrist flexion. Workers in certain trades cannot avoid working with hands overhead. The effect of overhead tasks on upper extremity MSDs, including carpal tunnel syndrome (CTS), is unclear. However, overhead work greater than two hours per day has been reported to significantly predict CTS symptoms in construction trades. The purpose of this study was to compare effects of hand elevation and wrist position on pulse rate and long finger mean arterial pressure (MAP) and thus tissue perfusion. Twenty healthy subjects (five female and fifteen male subjects, mean=31 yrs, range 21-47) consented to participate in this study. Blood pressure was measured in bilateral long finger using oscillometric monitors with simultaneous pulse rate measured via radiotelemetry. Two measurements were taken at each of five right hand elevations relative to heart level (0, ±20, ±40 cm) with two wrist positions (neutral and flexed). ICC values from 0.979 to 0.734 were shown. Analysis of variance and post hoc pair wise comparisons were performed using Tukey’s Test. Digital artery MAP was inversely proportional to hand elevation across an 80 cm range regardless of wrist position (R2=0.979, F=758.65, p<0.0001). Compensatory pulse rate changes were absent. This model of MAP demonstrated 0.73 mm Hg/cm. These findings indicate a public health need to address overhead tasks as an occupational hazard and an MSD risk factor. Implications exist for position-induced hand ischemia.
Learning Objectives: 1-List three factors contributing to mean arterial pressure and tissue perfusion during upright posture. 2-Recognize the role of hydrostatic column effect in tissue nutrition during upright posture. 3-Discuss rationale for overhead task performance as an occupational hazard and a public health concern for carpal tunnel syndrome and other work-related musculoskeletal disorders.
Keywords: Occupational Safety, Ergonomics
Presenting author's disclosure statement:
Organization/institution whose products or services will be discussed: none
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.